Permeability tuner and operating mechanism therefor



Aug. 19, 1941. P K, MOGALL 2,253,304

PERMEABILITY TUNER AND OPERATING MECHANISM THEREFOR Filed Dec. 24, 19377 Sheets-Sheet 1 INVENTOR.

PH/L/P X: 6,44 1.

BY MAI@.@LZQ

ATTORNEY.

Aug. 19, 1941. MCGALL 2,253,304

PERMEABILITY TUNER AND OPERATING MECHANISM THEREFOR Filed Dec. 24, 19377 Sheets-Sheet 2 MIG@Q ATTORNEY.

Aug. 19, 1941. P, K, MCGALL 2,253,304

PERMEABILITY TUNER AND OPERATING MECHANISM THEREFOR Filed Dec. 24, 19377 Sheets-Sheet 3 Mi i INVENTOR. pH/L/P K We GALL.

ATTORNEY.

Aug. 19, 1941. MCGALL 2,253,304

PERMEABILITY TUNER AND OPERATING MECHANISM THEREFOR Filed Dec. 24, 19377 Sheets-Sheet 4 INVENTOR. H/L/P K McG/ILL.

/WWGM ATTORNEY.

Aug. 19, 1941. P, K, MOGALL 2,253,304

PERMEABILITY TUNER AND OPERATING MECHANISM THEREFOR Filed Dec. 24, 19377 Sheets-Sheet 5 PH/L /P K. Me 64/. L.

BY M

ATTORNEY.

Aug. 19, 1941. P, K, MCGALL 2,253,304

PERMEABILITY TUNER AND OPERATING MECHANISM THEREFOR Filed Dec. 24, 1957'7 Sheets-Sheet 6 I INVENTOR. PH/L/P K. M064 LL BY ME ATTORNEY.

Aug. 19, 1941. P, K, MOGALL 2,253,304

PERMEABILITY TUNER AND OPERATING MECHANISM THEREFOR Filed Dec. 24, 19377 Sheets-Sheet 7 INVENTOR. PH/L/P K. We GFILL ATTORNEY.

Patented Aug. 19, 1941 PERIVIEABILITY TUNER. AND OPERATING MECHANISMTHEREFOR Philip K. McGall, Chicago, Ill., assignor to JohnsonLaboratories, Inc., Chicago, 111., a corporation of Illinois ApplicationDecember 24, 1937, Serial No. 181,674 16 Claims. (01. 74-95) Myinvention relates to an improved construction of permeability tuner forradio receiving sets and similar purposes, comprising a plurality ofcombined capacitance and inductance units susceptible of being tuned toresonance at different frequencies, by changing the efiective inductanceof the inductance coils of said units. A tuner of the kind referred tomay consist of as many stages as desired, and it has the advantage ofsmall bulk per stage, adapting the tuner for use in receivers where thelarger bulk of variable condensers would be undesirable, if notprohibitive.

My invention also includes improved operating means for simultaneouslyand similarly varying the effective inductance of the inductance coilsof said tuner, to the end that the several tuner units or stages may besimultaneously tuned to resonance at any desired frequency ofalternating current impulses, within the range of the tuner. Saidoperating mechanism thus constitutes a gang control for tuning saidunits, and it is characterized by smoothness of action, absence of lostmotion, positive operation, and micrometric efiect, at the same timebeing simple and inexpensive to manufacture. Said operating mechanism isalso adapted for use for other purposes, as will more fully appearbelow.

My invention will be best understood by reference to the accompanyingdrawings illustrating a preferred embodiment thereof in which Fig. 1shows my improved tuner in plan view;

Fig. 2 is a side elevation of. the construction shown in Fig. 1;

Fig. 3 is a bottom view of the construction shown in Fig. 1;

Fig. 4 is a vertical, sectional view of the parts illustrated in Figs. 1and 3, taken along the line ,44 in the latter figures;

Fig. 5 shows in a view similar to Fig. 4 and to an enlarged scale, apart of the operating mechanism of the tuner, consisting of the devicesused to hold the operating rod in operative relation to the operatedrods of said operating mechanism, said operated rods being above saidoperating rod instead of below the latter as illustrated in Fig. 4;

Fig. 6 is a vertical, sectional view of the parts shown in Fig. 5, takenalong the line 8-6 in that figure;

Fig. 7 is a horizontal, sectional view to an enlarged scale, of a partof the construction shown in Fig. 1, taken along the line 1-4 in thatfigure;

Fig. 8 shows in a view similar to Fig. 5, a modified construction ofoperating mechanism, in

which one operated rod is employed instead of two of said rods as shownin Fig. 5;

Fig. 9 is a vertical, sectional view of the parts shown in Fig. 8, takenalong the line 9-9 in that figure;

Fig. 10 shows in a view similar to Fig. 5, a further modifiedconstruction of operating mechanism, in which two operated rods aremoved simultaneously in opposite directions by the operating rod,instead of in the same direction as illustrated in Fig. 5;

Fig. 11 is a vertical, sectional view of the parts shown in Fig. 10,taken along the line H-ll in that figure;

Fig. 12 is a right hand end view to an enlarged scale, of one of theoperated rod's shown in Fig. 3, and illustrates the manner of connectingsaid rods with the movable plate connected in turn with the cores ofmagnetic material to operate the same;

Figs. 13, 14 and 15 show respectively, modified means for connectingsaid operated rods with said movable plate;

Fig. 16 is a vertical, sectional view of the parts shown in Fig. 15,taken along the line I6-l6 in that figure;

Fig. 1'] is a horizontal, sectional view of the construction shown inFig. 1, taken along the line l1-l1, excepting that in this view .theshield of the sectioned tuner unit is shown in side elevation, and thecover of the tuner is shown in place;

Fig. 18 illustrates in a view similar to Fig. 17, the combination of twotuners of the construction illustrated in Figs. 1 to 4 inclusive, toillustrate the tuning of two multi-stage tuners, by means of a singleoperating rod;

Fig. 19 illustrates diagrammatically, the adaptation of my improvedtuner to a remote control system;

' Fig. 20 is'a horizontal, sectional view of a part of the structureshown in Fig. 4, taken along the line 20-40 in that figure;

Figs. 21 and 22 illustrate respectively in views similar to Fig. 5,modified forms of operated rods for actuationby the operating rod;

Fig. 23 shows in plan view and partially in horizontal sectional view, amodified form of operating mechanism for my improved tuner construction;

Fig. 24 is a horizontal, sectional view of the structure shown in Fig.23, taken along the line 24-24 in that figure;

Fig. 25 is a vertical, sectional view of the structure shown in Fig. 23,taken along the line 25-25 in that figure;

Fig. 26 is a vertical, sectional view to an enlarged scale, of thecarriage mounting rod and its manner of support, taken along the line26-26 in Fig. 25;

Fig. 27 is a right-hand elevation of the parts shown in Fig. 26;

Fig. 28 is a horizontal, sectional view of the structure shown in Fig.27, taken along the line 28-28 in that figure;

Fig. 29 is a horizontal, sectional view of fastening and tensioningdevices employed in connection with the operating cable illustrated inFigs. 23 and 25, this view being taken along the line 2929 in Fig. 25;

Fig. 30 is a vertical, sectional view showing the manner of securing theother end of the operating cable to the carriage, this view being takenalong the line 3il3ll in Fig. 25;

Fig. 31 is a horizontal, sectional view to an enlarged scale, throughthe mounting devices employed to support one of the tuning cores of thedevice, this view being taken along the line 3l3l in Fig. 24;

Fig. 32 is a vertical, sectional view through a part of the constructionshown in Fig. 31, taken alon the line 32-32 in that figure;

Fig. 33 shows in elevation, the diaphragm forming a part of the coresupporting structure shown in Fig. 31, this view being taken along theline 33-33 in that figure;

Fig. 34 shows in elevation to an enlarged scale, the stop mechanismemployed to limit rotation of the operating shaft of the device, thisview being taken along the line 3434 in Fig. 25;

Fig. 35 shows in elevation to an enlarged scale, one of the discsemployed in the stop mechanism illustrated in Fig. 34;

Fig. 36 is a top view of the disc shown in Fig. 35;

Fig. 37 is a vertical, sectionaLview, of the disc shown in Fig. 35,taken along the line 31-31 in that figure; and

Fig. 38 shows in perspective view, the underside of the cover of thetuning device, to show certain shields secured thereto.

Similar numerals refer to similar parts throughout the several views.

As shown in Figs. 1 to 4 inclusive, my improved tuner consists of ahousing comprising a bent sheet metal plate l0 forming the front andside walls of said housing, and a sheet metal shelf ll having front andside flanges secured respectively to the front and side walls of theplate ID, the front flange of said shelf extending upwardly and its sideflanges extending downwardly. Said shelf II is also provided with adownwardly extending flange at its rear edge. Above the shelf H, thefront wall of the housing has secured to it a plurality of blocks I2 ofinsulating material, each of which blocks supports with a sliding fit,the front end of a tubular support l3 of insulating material on whichthe inductance coil 14 of the corresponding unit ,of the tuner, iswound. The rear end of each insulating tube I3 is supported with asliding flt, in a small plate E5 of insulating materialwhich is in turnsupported from the shelf II by a metal angle bracket. l6. As shown inFig. 20, the front end of the tube i3 contains a cross member 11connected at its ends with said tube, which cross member is con nectedby a stud I8 with the central portion of a flat spring l9 resting at itsends against the corresponding block I2. A screw 20 threaded through thefront wall of the tuner housing, rests at its inner end against themid-portion of the spring l9, said spring having a conformation movingthe tube l3 to its extreme forward position when the screw 20 is turnedto move it forwardly away from the block H2. The spring I9 and the partsdescribed as cooperating therewith, constitute a means for movingaxially the tube I3 and the coil l4 carried thereby, to align said coilsrelatively to each other for effective and accurate gang operation ofthe inductance changing devices respectively associated with said'coils,by the common operating mechanism below described.

Each of the tubes I3 contains a core 2| of magnetic material, preferablycomminuted magnetic material compressed into solid form, which core maymove freely axially in the tube l3 to change as desired, the effectivepermeability of the magnetic path through and around the correspondingcoil 44, and correspondingly changes the inductance of said coil. Therear end of each core 2! is connected with a short rod 22, the rear endof which is connected with and supported by a small plate of insulatingmaterial 23, which, as shown in Fig. 7, is rigidly connected with theupper portion of metal bracket 24 extending through a slot 25 thereforin the shelf H, shown in Figs. 1 and 3. As shown in Figs. 3 and 7, thelower portion of each bracket 25 extends through an opening therefor inan operating plate 26, and is rigidly secured below said plate to aflange 26a extending downwardly from the rear edge of said operatingplate.

As shown in Figs. 1, 3 and 4, the shelf H has formed therefrom upwardlyprojecting ribs 21 extending from front to rear of said shelf betweenthe coils 14, forming corresponding grooves in the lower surface of saidshelf. As shown in Fig. 4, each of the ribs 21 engages the-lowerportions of adjacent shields 28 provided to enclose the coils l4 andtheir cores 2|, to hold said shields agairist lateral movement, andcentrally around said coils l4. Each of said shields 28 is provided witha longitudinal slot 28a in its bottom wall, to clear the correspondingbracket 24 and to also clear the connection between the correspondingbracket IE and the shelf II. The opposite side edges of the horizontalportion of each of the brackets I6, are off-set upwardly from the shelfII, to clear the portions of the corresponding shield 28 adjacent itsslot 28a, whereby the bracket l6 serves as a guide in moving the shieldaround the coil l4, and holds the shield adjacent the shelf ll. Each ofthe blocks 12 fits in the open end of the corresponding shield 28, as aresult of which the shields when in place, are held at their front endsagainst lateral movement in any direction. The rear ends of said shieldsare held against movement, as below described.

The operating plate 26 as shown in Fig. 3, is shorter from front torear, than the shelf H, so that its operating movement is equal to thetuning movement to be imparted axially to the cores 2|. The plate 26 isprovided with upwardly extending ribs 29 fitting the grooves in the ribs21, to guide the plate 26 in its movement under the shelf ll. 3| extendhorizontally from the front wall of the tuner housing to the rear flangeon the shelf H, to which their ends are rigidly secured, the upper edgesof said bars being spaced slightly from the operating plate 26, theflange 26a of which is provided with apertures through which said bar Asshown in Figs. 3 and 4, bars 30 and extend with sliding fits. In thespaces between the bars 39 and 3| and the plate 26, flat springs 32carried by said plate are disposed which press the plate against theshelf II and hold the ribs 29 in sliding engagement with the grooves inthe ribs 21. The lower edges of the bars 39 and 3| are somewhat abovethe bottom of the housing l9, to clear the cover of the latter, as belowdescribed. The plate 26 thus constitutes a means for impartingsimultaneous and equal movement to the cores 2|, making gang tuning ofthe several inductances possible for different frequencies within therange of the tuner.

As indicated diagrammatically in Fig. 4, each of the blocks l2 carries afiat capacitor 33 having terminals 34 and 35, for connection with theterminals of the corresponding coil H, which terminals 34 and 35 arealso the terminals of the corresponding unit of the tuner for connectionas desired, according to the requirements of the circuit or hook-up withwhich the tuner is used, whether superheterodyne, tuned radio frequency,or otherwise. The capacitors 33 are of any kind well known in the artand preferably provided with suilicient adjustment for aligningpurposes,but are otherwise fixed.

In constructing the tuner, the coils H are wound to have as nearly aspossible, identical electrical characteristics, and the cores 2| aremade as closely as possible, duplicates as to dimensions andpermeability. The coils and cores are then mounted as described, and byaligning the coils by the screws 29, the same inductance relation isestablished between each coil and its core, as between each other coiland its core. Then, preferably with the cores drawn to the limit oftheir movement from within the coils, each unit of the tuner is tuned toresonance by aligning adjustment of its capacitor 33, and the tuner asto all of its units or stages, is in tune or resonance for the highestfrequency of the range of the tuner. Movement of the cores 2| into thecoils M by the operating plate 26, equally increases the permeability ofthe magnetic paths of the several coils for any particular position ofsaid cores, correspondingly and equally increasing the inductance ofsaid coils and establishing a tuned or resonant condition of all of theunits or stages of the tuner for any desired frequency within the rangeof the tuner, which is lower than the limiting high frequency of saidrange.

The means I employ to operate the plate 26, consists as shown in Figs. 3and 4, of an operating rod 36 'having rotary movement, which rod extendsperpendicularly through one of the side walls of the housing I9 andthrough the bar 3|, a bushing 31 being mounted in said side wall toconstitute a bearing for said rod, which rod is prevented from movingaxially in said bearing by split rings 39 carried by said rod at theends of said bushing. Two operated rods 39 are mounted below the rod 36,between and parallel with the bars' 39 and 3|, with their rear endsattached to the flange 26a. The rod 36 is provided with grooves 36a inline with the rods 39, in which grooves the rods 39 are held infrictional engagement by rollers 49 below said rods 39, said rollers 49being pressed upwardly against said rods 39 and in turn pressing saidrods upwardly into the grooves-36a, by a spring 4| extending at. itsmid-portion over and pressing downwardly against the rod 36, and at itsends extending under and pressing upwardly against the mid-portions ofthe rollers 49. In Figs. 5 and 6, the relation between the rod 36 andthe rods39 is more clearly shown. In these figures the rods 39 are abovethe rod 36 instead of below the latter rod as shown in Fig. 4, but therelation between said rods operatively, is the same in both cases.Asshown in Fig. 5, the grooves 36a are provided with inclined sidesurfaces diverging outwardly, said grooves being deep enough to clearthe surfaces of the rods 39 which are nearest the axis of the rod 36, sothat the rods 39 engage only said side surfaces. Between the grooves36a, the rod 36 is provided with a groove 36b containing the mid-portionof the spring 4|, and the rollers 49 are provided at their mid-portionswith grooves 49a containing the end portions of said spring. The ends ofthe spring 4| are extended sufliciently around the rollers 49, so thatin use, rotation of the rod 36 and the resultant longitudinal movementof the rods 39, will rotate the rollers and cause them to slip at theirpoints of engagement .with said spring, without changing the generalrelation of the spring to the rollers 49. By engaging the surfaces ofthe rod 36 and of the rollers 49 which are remote from the surfaces ofengagement between the rod 36 and the rods 39, the tendency of thespring 4| to elongate or straighten, presses the rollers 49 towards therod 36, and maintains the frictional engagement between the rod 36 andthe rods 39. This produces a smooth and even longitudinal movement ofthe rods 39 by rotation of the rod 36, without any irregularity ofaction, which makes possible exact and smooth operation of the movableparts of the tuner, even in imperceptible amounts, a condition greatlyto be desired in effecting exact tuning. As shown in Figs. 1 and 2, therod 36 has-secured to its outer end, an operating knob 42, and the muchgreater diameter of the knob than the diameter of the surfaces of therod 36 engaging the rods 39, gives the operating mechanism a micrometricaction, which also facilitates exact tuning. It will be noted in Fig. 6that the radius'of curvature of the curved end portions of the spring 4|engaging therollers 49, is substantally greater than the radius ofcurvature of the surfaces of said rollers 49 engaged by said spring. Asa result, when the tuner is substantially in tune for a desiredfrequency, and exact tuning is required, a small amount ofrolling'action of the rollers 49 on the spring 4| occurs withoutslippage of said parts 2:283:05]. oither bwlliich further facilitateseffecting un ng, y essenin atmg rod 36. g the drag on the oper- With theoperating mechanism described, several complete rotations of the rod 36are required to move the plate 26 through its tuning range and to affordan indication of the frequency for which the tuner is adjusted at anytime the plate 26 is provided with an arm 43 (Figs: 1, 2 and 3),extending through a slot 44 in a side wall of the housing l9 (Fig. 2),which arm is connected with an indicating pointer 45 adjacent a scale 46on the housing, calibrated in any desired units. Obviously, anyequivalent indicating means operated by the arm 43 may be employed asdesired, depending upon the location of the tgner and the partsassociated therewith in any c se.

To enclose the operating mechanism, a cover .plate 41 (Fig. 17) isemployed. With the unit top of the rear ends of said shields, the rearwall 41b of said cover plate extends adjacent the rear end walls of theshields 28, and the bottom wall He of said cover plate extendshorizontally in the bottom plane of the tuner housing ID, a front flange41d on said cover plate extending upwardly just inside of the front wallof the plate 10 of the tuner housing. The cover plate is of a widthequal to the distance between the side walls of the platen)? and restsbetween said side walls and on the lower edges of the downwardlyextending side flanges of the shelf ii, the flange 41d being between thefront ends of said side flanges, and the front wall of the plate in.This completely encloses the tuner, and produces a self-containedstructure that is much more compact than is possible by the use ofconventional interleaved variable capacitors, which structure is acomplete multi-s'tage tuner that is thoroughly shielded and entirelyenclosed, and requires in addition, only suitable radio tubes, asuitable current source, and wiring therefor, connected with the tunerin accordance with a desired hook-up or circuit, to make an operativetuning system.

It will be understood that I do not limit myself in constructing thetuners described, to the particular number of units illustrated, sinceeach tuner may consist of as many units or stages as desired. In Fig. 18I illustrate means that may be employed to operate and tune two completetuners of the kind described, by a single operating rod. Part of a firsttuner as above described, is shown, having a housing ill, a shelf ll,shields 28, an operating plate 26 and an operating rod 36. A secondsimilar tuner is shown, having a housing Illa, a shelf Ha, shields 28band an operating plate 26b, but no operating rod. The bottom edges ofthe housing l are held against the bottom edges of the housing Illa, bya cover plate 48 secured to the rear flanges oi the shelves H and Ho,which cover plate has upper and lower flanges 48a extending over the endportions of the shields 28 and 28b. The front walls of the housings i9and Illa are held together by a connecting plate 49 secured to saidfront walls. The flanges 26a 4 and 260 of the operating plates 26 and26b results as to the second tuner, and all of the units or stages ofboth tuners are thus simultaneously operated and tuned by means of asingle op- ,erating rod. Thus a plurality of tuners, each complete forits intended purpose and consisting of as many stages as desired, may besimultaneously tuned by a single operating rod, and said complete tunersmay be severally used for any purposes desired and either simultaneouslyor alternately, for example, as tuning means for different frequencybands.

As illustrated in Fig. 19, my tuner described;

is adapted for use in any case where the tuning units must have onelocation and the operating means or controlling devices must have asecond location which may be remote from said flrstlocation. In thisfigure my tuner is shown diagrammatically at Ill, its operating rod 36being connected by a flexible shaft 5| with an operating knob 52 on acontrol board 53 remote from the tuner Q0. The arm 43 of the tuner, isconnected with a wire 54 extending through a tube 55 to the controlboard 53, where said wire is connected with a pointer 56 movable by saidwire along a scale 51 carried by said control board. The ends of thetube 55 are supported by brackets 58 and 59 carried respectively by theturner l9 and the control board 53.

The manner of operating the frequency indicating pointer 56 asdescribed, gives a correct indication at any time of the frequency towhich the units of the tuner are tuned, in the system of units used inlaying out the scale 51, regardless of whether there is slippage in thefriction mechanism above described between the operating rod 36 and thecores 2i, since the knob 52 is not relied upon to indicate by itsangular position, the frequency for which the tuner is set at any time.Although there is little probability of slipp e between the operatingrod 36 and the operated rods 39 described in connection with Figs. 3 to6 inclusive, such slippage is possible unless prevented. I eliminate thepossibility of \such slippage to an appreciable extent, by securing tothe inner end of the rod 36, a pinion 69 (Figs. 3 and 4), meshing with arack 6| disposed parallel with the operated rods 39 which rack isrigidly secured at one end to the flange 26a. The other end 65a of therack 6| is in sliding engagement with the upper surface of the bar 30,thereby holding the rack in mesh with the pinion 60. The pitch diameterof the pinion 60 should equal the diameter of the contact circles in thegrooves 36a with the rods 39 to insure against slippage between theoperating rod 36 and the operated rods 39, due to the action of saidpinion.

The operated rods 39 may be connected with the flan'ge 26a of theoperating plate 26, in any one of a number of ways, several of which areshown in Figs. 12 to 16 inclusive. In each of these cases, each of therods 39 is provided with a circumferential groove 39a near its end tofacilitate said connection. In Fig. 12 the flange 26a is provided withan edge slot 26d fitting the groove 39a, and after the rod 39 is pressedto the bottom of said slot, an edge tongue 26a of the flange 26aadjacent said slot, is forced over and into the slot 26d and into thegroove 39a, locking the rod 39 in said slot. In Fig. 13 the flange 26 isprovided with clearance holes 269 for the rods 39, and after they areinserted in said holes with the adjacent parts of the flange 26 in thegrooves 39a, the rods 39 are held in the position shown in Fig. 13 by aspring 62bent at its midportion to go over the edge of the flange 26fwith the ends of said spring on opposite sides of said flange andextending under and partly around and pressing upwardly on the rods 39respectively. In Fig. 14, the flange 26h is provided with edge slots 269fitting the grooves 39a in the rods 39, and when said rods are pressedto the bottoms of said slots, they are held in the position shown inFig. 14 by a spring 63 bent at its mid-portion to go through a hole 291in the flange, with the ends of said spring extending on opposite sidesof said flange and over and pressing downwardly on said rods 39respectively. As shown in Figs. 15 and 16, the flange 26k is providedwith a clearance aperture 26m for each of the rods 39, and a U-shapedmetal clip 64 having similar clearance apertures through its legs, isemployed. The clip is placed on the flange with the clip apertures inline with the flange aperture 26m, the grooved end of a rod 39 isinserted through said apertures with the groove 39a in line with theflange 28k, and a set screw 85 threaded through the mid-portion of theclip 64 and resting against the edge of the in many equivalent ways asfar' as operation and results are concerned, without departing from myinvention in its generic aspect. Essentially my improved operatingmechanism includes a rotary operating rod, an operated rod to whichmovement is imparted axially by angular moverod. instead of one springas shown in'Figs. 5 and 6.

In Figs. and 11 I show a modification of the operating mechanism lastdescribed, in which two operated rods 38b are in frictional engagementwith the inclined side walls of the groove 3811 in the operating rod360, one of the said rods 88b being above and the otherbeing below theoperating rod, and each of said operated rods 3% being held inengagement with the operating rod 880 by a pair of springs 66 in themanner described in connection with Figs. 8 and 9. The two grooves 36ain the operating rod 36c, receive the end portions of both sets 01'springs, the parts being of the same construction and operating in thesame manner as described in connection with ment of said operating rod,there being frictional engagement between said rods resulting preferablyfrom substantially opposed surfaces of or carried by one of said rodsengaging correspond- .ingly opposed side surfaces of a groove in orcarried by the other of said rods, said surfaces being held infrictional engagement with each other by pressure of an amountdetermined by the degree of said frictional engagement retion intotranslatory or axial motion of an operated member or rod, as long as theforce so transferred is within the limits of the frictional engagementreferred to. v

In Figs. 8 and 9 I show a modified form 01' operating mechanism in whichbut one pressure roller and one operated rod are use, instead of two ofsaid rollers and two of said rods, as illustrated in Figs. 3, 4, 5 and6. As shown in Fig. 8, the operating rod 360 is provided with a groove36d having outwardly diverging side walls and engaging an operated rod89b in said groove, in the same manner that each of the grooves 36aengages a corresponding rod 39 as above described in connection withFigs. 5 and 6. On each side of the groove 36d, the rod 380 is providedwith a groove 36c containing one end portion of a spring 66, the otherend portion of which is in a groove 61a in a roller 61, which roller isprovided with a central groove 81b receiving the operated rod 39b. Theform of the springs 86 which press the roller 61 against the operatedrod 3% and so press the operated rod into the groove 36d, is shown inFig. 9. which also shows the position of the roller 61 immediately overthe operating rod 360, this view further illustrating the shape of theend portions of each of the springs 86, which permits a small amount ofrolling movement of the roller 61 onsaid springs. in making accurateadjustments of the rod 39b. This construction is adapted to move notonly rigid operated rods, but also operated rods that are more or lessflexible, whereas the construction shown in Figs. 5 and 6 is adaptedparticularly for use with operated rods that are rigid and have littleflexibility. A further advantage of the construction shown in Figs. 8and 9, is that greater pressure of the operated rod against theoperating rod may readily be obtained, as a result of using two springsper roller and per operated .Figs. 8 and 9, and the only differencebeing that two operated rods 39b are employed. This constructionprovides for moving operated mechanisms in different directions fromeach other, by a single angular movement of an operating rod.

While I have so far illustrated the operated rods as having circularcross-sections, it will be understood that they maybe of any form ofcross-sections, that will effect frictional engagement of the Enddescribed, with an operating rod. For example, in Fig. 21 Iillustrate afiat operated rod 68 having frictional engagement at its edge portions,with the outwardly diverging side walls of a groove 69a in an operatingrod .59, it being understood that the rod 68 may be held in saidfrictional engagement, by any of the means above described and not shownin Fig, 21, to avoid needless duplication. In Fig. 22 I show amodification of the constructionshown in Fig. 21, in which a fiatoperated rod 10 and an operating rod II are employed, which have thesame frictional relation to each other as the rods 68 and 69 shown inFig. 21, and in addition, the groove Ha in the rod II, whichfrictionally engages the edge portions of the rod 10, carries at itsmid-portion, outwardly extending gear teeth H b meshing withcorresponding rack teeth 10a in the lower surface of the rod 10, toprevent relative displacement between the rods 10 and H due to slippageat their'suriaces of frictional engagement, thereby avoiding the needfor an additional gear and a separate rack for that purpose. In thetuner construction illustrated in Figs. 23 and 24, a sheet metal casing80 has secured to one of its end walls and in parallel, horizontalarrangement. a plurality of shield cans 81 by means of bolts 82, each ofsaid shield cans having mounted therein. and at the end of said canadjacent the mounting wall of the casing 80, a head 8301 insulatingmaterial which supports a tube 84 of insulating material carrying aninductance coil 85. The end of each of the. shield cans remote from themounting wall of the casing, is closed and provided with a central borefitting the end of the tube 84 remotefrom the head 83. said tube 84extending through the said shield end wall to support the tube andinductance coil centrally in the shield can. The head 83, also supportsbetween said head and the mounting wall of thecasing, an adjustablecapacitor 86 for tuning the corresponding inductance coil 85 to adesired frequency, so as to align the resonant frequencies of the coiland capacitor combinations at any desired frequency of a range offrequencies. Each of the tubes 84 has mounted therein a cylindrical core81 of powdered iron, which is an easy sliding fit in said tube, so thatby movement of the core into and from the inductance coil 85 on thetube, the inductance of the coil may be changed to tune the coil andcapacitor combination, to any desired frequency in a given range offrequencies. The cores 81 are secured at their outer ends to ahorizontally movable carriage 99 supported for movement parallel withthe tubes 84 and under the shield cans 8|, by a rod 9l supported by theend walls of the casing 89, on which rod said carriage is a sliding fit.A cross-shaft 92 is mounted horizontally in the casing in line with therod 9!, said shaft being supported by the casing and by said rod SI forrotary movement, in a manner to be described. The shaft 92 is engaged byan operating cable 93 which encircles said shaft in such a manner thatthere will be no slippage between the shaft and the cable, and the endsof the cable are secured to the end walls of the carriage 99 in a mannerto be described. An operating rod 99 having secured thereto an operatingknob 99, extends through a bearing 96 in one of the side walls of thecasing, and into'the corresponding end of the shaft 92, to which it issecured in any desired manner, for example, by a set-screw 9?. Theopposite side wall of the casing is provided with a similar bearing 99afor the operating rod 99, so that the shaft 92 may be placed on theother side of the carriage supporting rod 9i, and the operating rod 94may extend from the opposite side of the tuning device, where it isdesired to assemble the tuning device for .operation from its side whichis opposite to that which is indicated as the operating side in Fig. 23.

As shown in Fig. 24, the end walls of the carriage 99 are flangedtowards each other at 99a and 99b to form bearings engaging thesupporting rod 9| with an easy sliding fit.

As shown in Fig. 25, the shaft 92 is provided at one end with a portion920 of reduced diameter, and is supported for turning movement in acorresponding horizontal bore in the supporting rod 9|, the oither endof said shaft being provided with a bore 92b to receivethe end portion94a of the operating rod 99, which is of reduced diameter to fit saidbore. The shaft 92 is in rolling engagement with the upper edge of aflange 99c extending upwardly from the side edge of the carriage 99, inwhich position said flange is held by a fiat spring 99 between saidcarriage and the bottom of the casing 89, said spring being held in anysuitable manner against movement with the carriage 99 and under theshaft 92. The spring 98 by maintaining the engagement referred tobetween the flange 99c and the shaft 92, prevents -rocking movement ofthe carriage 99 on its supporting rod 9|. It will be noted that the borein the supporting rod 9i for the end 920; of the shaft 92, extendshorizontally through said supporting rod, as a result of which the shaft92 may be mounted between said supporting rod 9i and either side wall ofthe casing, as desired. Outside of the casing, the operating rod 94 hassecured thereto a collar 99 holding discs I99, IM and I92 in contactwith each'other between said collar 99 and the adjacent side wall of thecasing, said discs serving as below described to constitute a stopmechanism limiting rotation of the operating rod 94.

As shown in Fig. 26, the supporting rod 9i is provided at one end with aportion 9la of reduced diameter fitting a corresponding bore in the endwall of the casing. The other end 9") of said supporting rod is notreduced in diameter and fits a bore 89a in the end wall of the casing,which bore is connected with a slot 89b extending through the upper edgeof said casing end wall,

said slot being narrower than the diameter of said bore. Adjacent theend 9": of the rod M, the said rod is grooved at Me to a diametersubstantially equal to the width of the slot 899, so that when 'saidgroove 9Ic is in alignment with said slot, the corresponding end of thesupporting rod 9i may beraised through said slot and from engagementwith the corresponding end wall of the casing 89. Adjacent the end SI?)of the rod 9i, the groove 9lc is further reduced in diameter to form asecond groove 9Ib to receive a locking plate I99.

As shown in Fig. 27, the plate I99 is slotted through one of its ends atI93a, the width of the slot being substantially equal to the diameter ofthe groove 9| d, so that when the groove 9Id is inside of thecorresponding end wall of the casing 89, the locking plate I93 may bemoved longitudinally into engagement with said groove M11, in whichposition it may be held by a lug 99c extending from the correspondingend wall of the casing 89, as shown in Fig. 28. As a result of thisconstruction, when the locking plate I93 is in engagement with thegroove 9Id and with the lug 890, the supporting rod Si is held immovablelongitudinally, in the casing 89, and when for any reason it is desiredto remove the supporting rod from the casing, all that is required is tofirst disengage the locking plate from the lug 890, to then move thelocking plate 93 endwise from engagement with the groove Sid, and tothen move the supporting rod 9i longitudinally sufiiciently to bring thegroove 9Ic into alignment with the slot 89b, for which relation of theparts the grooved end of the supporting rod may be readily lifted fromengagement with the corresponding end wall of the casing 99, and the rodmay then be disengaged from the other end of the casing. The lockingplate I93 is preferably made of spring metal and bent sufliciently sothat it will exert a desired amount of pressure on the rod 9| when inplace, to hold the shouldered portion Bio. of said rod tightly againstthe corresponding end wall of the casing.

As shown in Fig. 29,- the left-hand end of the cable 93 illustrated inFigs. 23 and 24, is secured to the corresponding end wall of thecarriage 99 by means of an eyelet I99 which extends through a flatspring I95 and with a free fit through the corresponding end wall of thecarriage 99, the end of the cable being knotted outside of the head ofthe eyelet I99, to flatten the spring I95 to a desired degree from itscondition of normal curvature, so that the desired tension may becontinually-exerted on the cable 93. The eyelet I99 besides holding thespring I95 in alignment with the cable opening through the end wall ofthe carriage 99, also provides a rounded opening for engagement by theknot of the cable which prevents damaging the cable and its knot. The

other end of the cable 93, as shown in Fig. 30, extends through asimilar eyelet I96 from which the cable is led upwardly along the outersurface of the corresponding end wall of the carriage '99 and clamped indesired position by washer I9! by means of a screw I98 extending intothe end wall of the carriage. By proper initial adjustment, the cablemay be subjected to sufiicient initial tension to take up its stretchingtendency, and the spring I95 insures the taking up of any furtherstretch that may occur in the cable, so that it is maintained in tightcondition at all times, with the result that the operation of thecarriage by rotation of the operating rod 94 positively drives thecarriage without lost motion is of somewhat smaller diameter than thediameter of the body portion of said shaft, the difference in diameterbeing preferably equal to the diameter of the cable, so that theeffective diameter of the cable wrapped around the said shaft portion92c will produce longitudinal movement of the carriage 90 precisely atthe same of a shouldered stud I09, the other slotted endportion of whichis threaded at I91; and in threaded engagement with a metal collar IIOrigidly secured to the central portion of a thin diaphragm I I I. Theouter edge portion of the diaphragm III is clamped to the end wall-ofthe carriage 90 by a clamping ring H2 and clamping screws II3, the innerdiameter of the clamping ring II2 being in line with a conespendingaperture through the end wallof the carriage 90, said diameter beingsufficiently larger than the external diameter of the collar IIO so thatthe central portion of the diaphragm III is relatively free to bend to alimited extent. .The collar III) is provided through one ofits sideswith a slot IIOa. extending somewhat into the threaded bore through saidcollar, and in said slot a bent wire spring III is disposed in such amanner as to press against the threaded portion I09!) and also againstthe collar IIO, with sufficient force to prevent the accidental turningof the threaded portion I09b in the collar H0. The outer edge of thediaphragm III, as shown in Fig. 33, is preferably provided withclearance notches I I Ia in line with the clamping screws II3, tofacilitate assembling the parts, and adlusting the diaphragm in exactalignment with the axis of the corresponding core 81. The flexibility ofthe diaphragm III, permits the collar II0 to adjust itself axially withthe axis of the corresponding core and coil mounting tube, if for anyreason they are slightly out of alignment, so that the carriage may beoperated freely without resultant binding of the cores in the coilmounting tubes, which might be the case if the cores did not have theflexible mounting referred to. The threaded portion I091) connected witheach of the cores permits each core to be moved longitudinallyrelativelyto the carriage 90, by turning the stud I09 relatively to its collarIII'I, so that a desired amount of inductance of the correspondinginductance coil 85 may be secured at any desired frequency of a tunedband, and

this feature of adjustment further provides that,

the inductances may be aligned with each other to facilitate gangoperation of the inductance variation for the several resonant circuitscontrolled by the tuning device.

In Figs. 34-37 inclusive, I illustrate the structure provided to limitrotative movement of the operating rod 84. This stop mechanism consistsof a plurality of discs of the same construction as that illustrated inFigs. 35, 36 and 37 for the disc I0]. Asjshown in these figures, thedisc is provided with a 'bore I0la which is a free flt on theoperatingrocl 94, and from the outer edge of the disc and at one sidethereof, two lugs "IOIb and lie project, between which lugs a third lugIOId is located, said lug I Mr! being offset from the plane of the discby an amount substantially equal to the thickness of the disc, while thelugs Nb and IOIc are in the plane of said disc. The discs I00, IM andI02 shown in Fig. 25, being all of the same construction, are mounted onthe operating rod 94 with their lugs I 0Id extending in the samedirection, and the disc I00 is rigidly secured to the collar 09 in anyconvenient manner not shown, and the lug I 0Id of the disc I 02 engagesa corresponding opening in the side wall of the casing which preventsrotary movement of the disc I02. Since the discs are held in engagementwith eacliother by the collar 99, the lug 10Id on the disc I00 is in theplane of lugs I0") and IOIc of the disc "II, and the lug IIlId of thedisc IIII is in the plane of the lugs IOIb and IOIc of the disc I02. Itwill be observed thatthe disc IOI is not connected with the operatingrod 94 and that it is not connected with either of the adjacent discs,or in other words, that it floats angularly on the operating rod betweenthe discs I00 and As a result of this construction, rotation of theoperating rod 94 in either direction rotates the disc I00 at the samerate and this rotation first results in engagement between lugs of thediscs I00 and IN, after which the disc IN is rotated with the operatingrod 94 until engagement between the lugs of the discs IOI and I02results, which prevents further rotation of the operating rod in thatdirection; beginning with that condition, rotation of the operating rod9| in the reverse direction, may continue freely until engagement in thereverse direction between the ings of each disc and its adjacent disc iseffected, which prevents further movement of the operating rod in thatdirection. It is obvious of course that as many floating discs may beemployed as desired, depending upon the amount of rotary movement thatis to be permitted in either direction.

In Fig. 38 I illustrate in perspective, the construction of the cover H4used to close the casing 80, which cover is provided with a U-shapedshield member II5 of sheet metal, the side walls of which are located tolie midway between the cores 8'! respectively when the cover is in placeon the casing, the ends of said shield entering slightly between theends of the shield cans 81, as illustrated in Fig. 23. The end wall ofthe cover is provided with apertures 4a in line with the studs I09, sothat core adjustment relatively to the carriage may be effected with thecover in place on the casing. The end Wall of the carriage 90 supportingthe cores 81, is slotted at 90d to clear the side walls of the shieldingmember Hi.

In connection with the diaphragms employed to connect the carriage withthe cores, said diaphragms may preferably be of thin flexible sheetmetal where there is no need to electrically insulate said diaphragms,and where for any reason the said cores must be insulated from thesupporting mechanism, said diaphragms may.

conveniently be of thin sheet insulating material such as Bakelite orthe equivalent.

In connection with the construction of operating mechanism illustratedin Figs. 23-38 inclusive, it will be noted that the cable 93 is notsecured to the shaft 92, but that the movement of the carriage 9|]results from the friction of the cable on the shaft. It .will further beobserved that the cable is subjected to a substantial initial tensionand that the ends of the cable extending to the carriage aresubstantially in line with each other; also, that the forces exerted bythe cable upon the carriage are equal and initial forces aresubstantial, there are no extraneous unbalanced forces of any kind.which require counteracting with the resultant possi-. bility ofintroducing opposition to the movement of the operating mechanism.The'result is that the operating mechanism has a smooth, uniform a andreliable movement throughout. With the type of operating mechanism shownin Figs. 1-22 inclusive, substantial forces are initially exertedbetween each operated rod and the operating rod by the springs androllers described, and in this case the lateral pressures developed bythe small inclination of the side walls of the groove or grooves in theoperating rod, produce forces which are balanced and self-contained inthe operating rod, and also produce balanced lateral forces which areself-contained in the operated rod or rods, the spring pressure exertedin holding the rods together being balanced against the operating andoperated rods so that thecsaid forces are balanced within the operatingmech anism considered as a whole. With this construction the only forcerequired to move the operating mechanism, is that required to overcomethe friction between the operated rod and the side walls of the grooveof the operating rod. Although this friction is of small amount, theentire similar load on the operating rod, represented by the forcerequired to bend, the cable 93 around the shaft 92, is even less, sothat the latter construction is somewhat easier to operate, andis,corresponding1y smoother in operation.

As a result of the substantial initial pressures employed in connectionwith the operating mechanism of either type disclosed, it will beobserved that the drive forces imparted to the operated member or rodmay readily be considerably greater than is actually required to movethe same, as a result of which I designate the operating mechanism ineach case as a positive-drive fricticn mechanism, the operating rod andthe operated member being connected in either case by positive-drivefriction gearing.

While I have shown my invention in the particular embodiment abovedescribed, it will be understood that I do not limit myself thereto, asI may employ equivalents thereof known to the art at the time of thefiling of this application, without departing from the scope of theappended claims.

Having thus described my invention, what I claimis:

1 Operating mechanism for a device of the class described, including incombination a housing rod having connection at its end portions with theend walls of said housing, a longitudinally movable carriage having endwalls provided with bearings engaging said supporting rod with a slidingfit, a rotary operating rod extending transversely of said supportingrod adjacent said carriage and supported by said housing, and

1 a flexible cable tightly wrapped around said opwith the end walls ofsaid housing, a longitudinally movable carriage having end wallsprovided with bearings engaging said supporting rod with gitudinallymovable carriage having end walls ing having side, bottom and end walls,a support- 25 a sliding fit, a rotary operating rod extendingtransversely of said supporting rod adjacent said carriage and supportedby said housing, a flexible cable tightly wrapped around said operatingrod and extending in opposite directions therefrom and connected withthe end walls of said carriage, saidcarriage having a flange extendingtowards and engaging said operating rod, and a spring holding saidflange in engagement with said operating rod.

3. Operating mechanism for a device of the class described, including incombination a housing having side, bottom and end walls, a supportingrod having connection at its end portions with the end walls of saidhousing, 2. ionprovided with bearings engaging said supporting rod witha sliding fit, a rotary operating rod extending transversely of saidsupporting rod adjacent said carriage and supported by said housing, aflexible cable tightly wrapped around said operating rod and extendingin opposite directions therefrom and connected with the end walls ofsaid carriage, said carriage having a flange extending towards andengaging said operating rod, and a spring holding said flange inengagement with said operating rod, the portion of said operating rodengaged by said cable being of smaller diameter than the portion of saidoperating rod engaged by said flange to compensate for the thickness ofsaid cable, whereby the carriage movement per rotation of said operatingrod producedby said cable is substantially equal to the circumference ofthe portion of said operating rod engaging said flange.

4. Operating mechanism for a device of the class described, including incombination a housing having side, bottom and endw'alls, a supportingrod having connection at its end portions with the end walls of saidhousing, a longitudinally movable carriage having end walls providedwith bearings' 'engaging said supporting rod with a sliding fit, arotary operating rod extending transversely of said supporting rodadjacent said carriage and supported by said housing, a flexible cabletightly wrapped around said operating rod and extending in oppositedirections therefrom and connected with the end walls of said carriage,and a spring connected with said cable and exerting tension thereon.

5. Operating mechanism for a device of theclass described, including incombination a housing having side, bottom and end walls, a supportingrod having connection at its end portions with the end walls of saidhousing, a longitudinally movable carriage having end walls providedwith bearings engaging said supporting rod with a sliding fit, a rotaryoperating rod extending transversely of said supporting rod adjacentsaid carriage and supported by said housing, a flexible cable tightlywrapped around said operating rod and extending in opposite directionstherefrom and connected with the end walls of said carriage, and a fiatspring on one of said carriage end walls and connected with thecorresponding cable portion and maintaining said cable under tension.

6. Operating mechanism for a device of the class described, including incombination a housing having side, bottom and end Walls, a supportingrod having connection at its end portions with the end walls of saidhousing a longitudinally movable carriagehaving end walls provided withbearings engaging said supporting rod with a sliding fit, a rotaryoperating rod extending transversely of said supporting rod adjacentsaid carriage and supported by said housing, a flexible cabletightlywrapped around said operating rod and extending in oppositedirections therefrom and connected with the end walls of said carriage afiat spring on one of said carriage end walls in line with said cable,and a headed tube extending through said spring and with a free fitthrough said end wall, the head of said tube resting against said springand said cable extending through said tube and secured adjacent the headthereof.

7. Operating mechanism for a device of the class described, including incombination a housing having side, bottom and end walls, a supportingrod having connection at its end portions ing for the inner end of saidoperating rod, and I one of said housing side walls having a secondbearing for said operating rod.

8. Operating mechanism for a device of the class described, including incombination a hous ing having'side, bottom and end walls, a supportingrod having connection at its end portions with the end walls of saidhousing, a longitudinally movable'carriage having end walls providedwith bearings engaging said supporting rod with a sliding fit, a rotaryoperating rod extending transversely of said supporting rod adjacentsaid carriage and supported by said housing, and a flexible cabletightly wrapped around said operating rod and extending in oppositedirections therefrom and connected withthe end walls of said carriage,said operating rod, being substantially parallel with the bottom wall ofsaid housing and in line with said supporting rod, and said supportingrod being centrally disposed between the side walls of said housing,said' supporting rod having a transverse bore therethrough constitutinga bearing for the inner end of said operating rod, and each of saidhousing side walls having a bearing for said operating rod in line withsaid transverse bore, whereby said -operating rod may be assembled insaid operating mechanism to project from either of the housing sidewallsas desired.

9. Operating mechanism for a device of the class described, including incombination a housing having side, bottom and end walls, a supportingrod having connection at its end portions with the end walls of saidhousing, a longitudinally movable carriage having end walls providedwith bearings engaging said supporting rod with a sliding fit, a rotaryoperating rod extending transversely of said supporting rod adjacentsaid carriage and supported by said housing, a flexible cable tightlywrapped around said operating rod and extending in opposite directionstherefrom and connected with the end walls of said carriage, and 'stopdevices for limiting rotary movement of said operating rod including aseries of apertured discs each having a first lug extending radiallytherefrom in the plane of the disc and also a second lug extendingradially therefrom and displaced from the plane of the disc, said discsloosely fitting said operating rod and being mounted thereon adjacenteach other and with said second lugs displaced in the same directionaxially of said rod, the first disc of said series being secured to saidoperating rod and the last disc of said series being secured to saidhousing with the second lug of each disc in the plane of the first lugof the next disc, whereby rotation of said operating rod may be limitedto a desired number of rotations determined by the number of discs insaid series and the angular extent of said lugs.

10. Operating mechanism for a device of the class described, includingin combination a housing having side, bottom and end walls, a supportingrod having connection at its end portions with the end walls of saidhousing, a longitudinally movable carriage having end walls providedwith bearings engaging said supporting rod with a sliding fit, a rotaryoperating rod extending transversely of said supporting rod adjacentsaid carriage and supported by said housing, and a flexible cabletightly wrapped around said operating rod and extending in oppositedirections therefrom and connected with the end walls of said carriage,said supporting rod having a transverse bore therein constituting afirst bearing for the inner end of said operating rod, and one of saidhousing side walls having a second bearing for said operating rod, saidoperating rod including an inner shaft portion extending from saidsupporting rod to said second bearing and an outer portion extendingthrough said second bearing and secured to said shaft portion.

11. Operating mechanism for a device of the class described, includingin combination a housing having side, bottom and end walls, a supportingrod having connection at its end portions with the end walls of saidhousing, a longitudinally movable carriage having end walls providedwith bearings engaging said supporting rod with a sliding fit, a rotaryoperating rod extending transversely of said supporting rod adjacentsaid carriage and supported by said housing, a flexible cable tightlywrapped around said operating rod and extending in opposite directionstherefrom and connected with the end walls of said carriage, saidsupporting rod having a transverse bore therein constituting a firstbearing for the inner end of said operating rod, and one of said housingside walls having a second bearingfor said operating rod, said operatingrod including an inner shaft portion extending from said supporting rodto said second bearing and an outer portion extending through saidsecond bearing and secured to said shaft portion,

i said shaft portion having a shouldered portionot reduced diameter atits inner end to fit said first bearing and having an axial bore at itsouter end, the outer portion of said operating rod being of reduceddiameter at'its inner end to fit said shaft bore, and fastening meanssecuring said. shaft portion to the outer portion of said operating rod,the outer end of said shaft portion being of larger diameter than thebore of said second' bearing, whereby said operating rod is restrainedfrom longitudinal movement.

12. Operating mechanism for a device or the class described, includingin combination a housing having side, bottom and end walls, a supportingrod having connection at its end portions with the end walls of saidhousing, a longitudinally movable carriage having end walls provided Ibore receiving and fitting the second end portion of said supportingrod, said second bore opening into a slot of less width than thediameter of said second bore, said slot extending through the upper edgeof said second end wall, said second end portion oi said supporting rodhaving a groove inside of said second end wall of a bottom diameter forfree movement in said slot, said groove having an axial width at leastat large as the thickness of said second end wall, and locking meansrestraining said supporting rod from longitudinal movement when in saidbores.

13. Operating mechanism for a device of the class described, includingin combination a'housing having side, bottom and end walls, a supportingrod having connection at its end portions with the end walls of saidhousing, a longitudinally movable carriage having end walls providedwith bearings engaging said supporting rod with a sliding fit, a rotaryoperating rod extending transversely of said supporting rod adjacentsaid carriage and supported by said housing, a flexible of saidsupporting rod being or reduced diameter and shouldered, and a fiatspring locking plate slotted to engage said second groove to hold saidsupporting rod against longitudinal movement relatively to said'housing.

14. Operating mechanism for a device of the class described, includingin combination a housing having side, bottom and end walls, a supportingrod having connection at its end portions with the end walls of saidhousing, a longitudinally movable carriage having end walls providedwith bearings engaging said supporting rod with a sliding fit, a rotaryoperating rod extending transversely of said supporting rod adjacentsaid carriage and supported by said housing, a flexible cable tightlywrapped around said operating rod and extending in opposite directionstherefrom and connected with the end walls of said carriage, a first oneof said housing end walls having a first bore receiving and fitting afirst end portion of said supporting rod, and the second of said housingend walls having a second bore receiving and fitting the second endportion of said supporting rod, said seoond bore opening into a slot (ofless width than the diameter of said second bore, said slot extendingthrough the upper edge of said second end wall, said cable tightlywrapped around said operating rod and extending in opposite directionstherefromand connected with the end walls of said carriage, a first oneof said housing end walls having a first bore receiving and fitting afirst end portion of said supporting rod, and the second of said housingend walls having a second bore receiving and fitting the second endportion of said supporting rod, said second bore opening into a slot ofless width than the diameter of said second bore, said slot extendingthrough the upper edge of said second end wall, said second end portionof said supporting rod having a groove inside of said second end wall ofa bottom diameter for free movement in said slot, said groove having anaxial width at least as large as the thickness of said second end wall,said groove containing a second groove of still smaller bottom diameter,said first end portion second end portion of said supporting rod havinga groove inside of said second end wall 01. a bottom diameter for freemovement in said slot,

said groove having an axial width at least as large as the thickness ofsaid second end wall,

said groove containing a second groove of still smaller bottom diameter,said first end portion of said supporting rod being of reduced diameterand shouldered, and a fiat spring locking plate slotted to engage saidsecond groove to hold said supporting rod against longitudinal movementrelatively to said housing, said second end wall having an extending lugengaging said locking plate and holding it in said second groove.

15. Operating mechanism for a device of the class described, includingin combination a housing, a supporting rod having connection at its endportions with said housing, a longitudinally movable carriage engagingsaidsupporting rod with a sliding fit, a rotary operating rod extendingtransversely of said supporting rod adjacent said carriage and supportedby said housing, and a fiexible cable around and driven by saidoperating rod and extending in opposite directions therefrom andconnected with saidcarriage.

16. Operating mechanism for a device of the class described, includingin combination a housing, two elements having relative rectilinearmovement and comprising a guide rod and a bearing member in slidingengagement with said guide rod, a first one of said" elements havingfixed support from said housing, a rotary operating rod extendingtransversely of said guide rod and supported by said housing, and afiexibie cable around and driven by said operating rod and extending inopposite directions therefrom and connected at its end portions with thesecond one of said elements.

- PI-HLIP K. MCGALLL CERTIFICATE OF CORRECTION. Patent No. 2,255,50LL.August 19, 19in.

PHILIP K. M cGALL.

It is hereby certified that error afipears in the printed specificationof the above numbered patent requiring correction as follows: Page 5,second column, line zip-25, for "cross-sections" read cross-section";page 6, secon d colmnn, line 11, for 91b read --9ld-- line 6 before"washer" Kin dartQF--e5' 'QFge-. l0, first column, line 57, claim 12,for at large 'read' --faa"lerge--; ind thet the said Letters Patentshould be read with thin correction therein that the same may conform tothe record of the ca se' gatent Oifice.

Signed ei d th1r28th day or October, A. D. 19in.

; Henry Van Arsdale, (Seal) Acting Commissioner of-Patents.

